EPA-600-R-12-636
EPA-600-R-12-637
EPA-600-R-12-638
www.epa.gov/narel
August 2012
Revision 0
Rapid Method for Fusion of Soil and Soil-Related
Matrices Prior to Americium, Plutonium, and
Uranium Analyses for Environmental
Remediation Following Radiological Incidents
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Radiation and Indoor Air
National Air and Radiation Environmental Laboratory
Montgomery, AL 36115
Office of Research and Development
National Homeland Security Research Center
Cincinnati, OH 45268
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Rapid Method for Fusion of Soil and Soil-Related Matrices Prior to Americium, Plutonium, and Uranium Analyses
Revision History
Revision 0 I Revision 0 I 08-31-2012 I
This report was prepared for the National Air and Radiation Environmental Laboratory of the Office of
Radiation and Indoor Air and the National Homeland Security Research Center of the Office of Research
and Development, United States Environmental Protection Agency. It was prepared by Environmental
Management Support, Inc., of Silver Spring, Maryland, under contract EP-W-07-037, work assignments I-
41 and 2-43, both managed by Dan Askren. Mention of trade names or specific applications does not
imply endorsement or acceptance by EPA.
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Rapid Method for Fusion of Soil and Soil-Related Matrices Prior to Americium, Plutonium, and Uranium Analyses
RAPID METHOD FOR FUSION OF SOIL AND SOIL-RELATED MATRICES PRIOR TO AMERICIUM,
PLUTONIUM, AND URANIUM ANALYSES
1. Scope and Application
1.1. The method is applicable to the fusion digestion of soil and soil-related matrices (e.g.,
sediments, dry deposition samples, loam, etc), prior to the chemical separation
procedures described in the following procedures (see Reference 16.1l):
1.1.1. Rapid Radiochemical Method for Americium-241 in Water.
1.1.2. Rapid Radiochemical Method for Plutonium-238 and Plutonium-239/240 in
Water.
1.1.3. Rapid Radiochemical Method for Isotopic Uranium in Water.
1.2. This is a general method for soil samples, dry paniculate deposition samples, and
sediments collected following a radiological or nuclear incident.
1.3. Alternative rapid methods exist for sodium carbonate fusion of radium (see Reference
16.2), and strontium (see Reference 16.3) in soil matrices. These fusion methods lead
into analyses using the published rapid methods for radionuclides in water (see
Reference 16.1).
1.4. The dissolution by fusion of soils, or related matrices, by this method is expected to
take approximately 2-3 hours per batch of 20 samples. This assumes the laboratory
starts with a representative, finely ground, 1-g aliquant of dried sample.2 Initial
sample combustion at 600 °C is necessary for removal of any organic matter prior to
fusion, unless it has been established that the amount of organic matter present will
not interfere with the analytical separations.
1.5. Soil samples must be dried and ground to at least 50-100 mesh size prior to fusion. A
Rapid Technique for Milling and Homogenizing Soil Samples is included as
Appendix A to this method.
1.6. As this method is a gross pre-treatment technique, to be used prior to other separation
and analysis methods, the user should refer to those individual methods and any
project-specific requirements for the determination of applicable measurement quality
objectives.
1.7. Application of this method by any laboratory should be validated by the laboratory
using the protocols provided in Method Validation Guide for Qualifying Methods
Used by Radioanalytical Laboratories Participating in Incident Response Activities
(see Reference 16.4), or the protocols published by a recognized standards
organization for method validation.
1 Revision 0.1 for all five rapid methods in water were released in October 2011 and are available at
www.epa.gov/narel/incident guides.html. These revisions addressed typographical errors, improved wording
consistency with other methods, and clarified some examples. There were no substantive changes to any of the
methods.
2 The laboratory should have a separate method for achieving sub-sampling of the sample based on grinding, mixing
and sizing the sample to achieve aliquant uniformity.
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1.7.1. In the absence of project-specific guidance, measurement quality objectives
(MQOs) for soil samples may be based on the Analytical Action Levels
(AALs) and Required Method Uncertainties (MMR and
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Rapid Method for Fusion of Soil and Soil-Related Matrices Prior to Americium, Plutonium, and Uranium Analyses
4.4. Samples with elevated activity or samples that require multiple analyses from a single
soil sample may need to be split after dissolution. In these cases the initial digestate
and the split fractions should be carefully measured to ensure that the sample aliquant
for analysis is accurately determined.
4.4.1. Tracer or carrier amounts (added for yield determination) may be increased
where the split allows for the normal added amount to be present in the
subsequent aliquant. For very high activity samples, the addition of the tracer
or carrier may need to be postponed until following the split, in which case
special care must be taken to ensure that the process is quantitative until
isotopic exchange with the yield monitor is achieved. This deviation from the
method should be thoroughly documented and reported in the case narrative.
4.5. The subsequent chemical separation methods for water samples, which are referenced
in Step 1 above, specify a sample size (in liters), which is used in the associated
calculation of activity, uncertainty, etc. When this fusion method is employed and
samples of a matrix other than water are analyzed, and/or the sample size is given in
units other than liters, consideration must be given to the sample size and units in
order to ensure accurate reporting of the sample activity and other quality parameters.
In the subsequent chemical separation methods, the appropriate sample size and units
should be substituted for the volume of water sample, in liters, discussed in those
methods.
4.5.1. When this method is employed and the entire volume of fused sample is
processed in the subsequent chemical separation method, the original sample
size and units are used in lieu of the water volume in all calculations, with the
final results reported in the units requested by the incident command, rather
than liters.
4.5.2. In cases where the sample digestate is split prior to analysis, the fractional
aliquant of the sample is used to determine the sample size. The calculation of
the appropriate sample size used for analysis is described in Step 12, below.
4.6. In the preparation of blank samples, LCSs and duplicates, care should be taken to
create these QC samples as early in the process as possible, and to follow the same
tracer/carrier additions, digestion process, and sample splitting used for the field
samples. In the case of this method, QC samples should be initiated at the point
samples are aliquanted into crucibles for the fusion.
4.7. Although this method is applicable to a variety of subsequent chemical separation
procedures, it is not appropriate where the analysis of volatile constituents such as
iodine or polonium is required. The user of this method must ensure that analysis is
not required for any radionuclide that may be volatile under these sample preparation
conditions, prior to performing this procedure.
4.8. Platinum crucibles are required to withstand the harsh conditions of the digestion and
fusion processes used in this method.
4.8.1. The laboratory must develop effective processes for cleaning crucibles. The
effectiveness of the cleaning process should be demonstrated through
measures such as measurements of fusion blanks.
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4.8.2. Segregation of crucibles used for low and high activity samples is
recommended to minimize the risk of cross-contamination while maximizing
the efficient use of crucibles.
4.8.3. If platinum crucibles are not available, an effective, alternate method is
available that uses zirconium crucibles. See Rapid Method for Sodium
Hydroxide Fusion of Concrete Matrices prior to Am, Pu, Sr, Ra, and U
Analyses (see Reference 16.7) and RapidRadiochemicalMethod'for Total
Radiostrontium (Sr-90) in Building Materials for Environmental Remediation
Following Radiological Incidents (see Reference 16.8).
NOTE: Certain transuranic materials, once used for production of high-Z fissionable materials, have
become stored as waste materials or may still be in use. Specifically, 252Cf and neutron-irradiated AmCm
sources potentially could be used in an RDD. These radionuclides and their progeny, if present, would
interfere with the alpha spectrometric analysis of 239+240pu and 241Am or 243Am.
5. Safety
5.1. General
5.1.1. Refer to your laboratory safety manual for concerns of contamination control,
personal exposure monitoring and radiation dose monitoring.
5.1.2. Refer to the laboratory chemical hygiene plan (or equivalent) for general
safety rules regarding chemicals in the workplace.
5.2. Radiological
5.2.1. Discrete Radioactive Particles (DRPs or Hot Particles)
5.2.1.1. Hot particles will be small, on the order of 1 mm or less. DRPs are
typically not evenly distributed in the media and their radiation
emissions are not uniform in all directions (anisotropic).
5.2.1.2. Soil media should be individually surveyed using a thickness of the
solid sample that is appropriate for detection of the radionuclide
decay particles.
5.2.2. The sample size initially dried and homogenized should be of adequate size to
conduct all required measurements but not too large as to cause a potential for
generating airborne contamination.
NOTE: The information regarding DRPs should accompany the samples during
processing as well as be described in the case narrative that accompanies the sample
results.
5.3. Procedure-Specific Non-Radiological Hazards:
5.3.1. This procedure employs molten salts generated at high temperatures
(-1,000 °C) in an open flame. The operator should exercise extreme care
when using the burners and when handling the hot crucibles. Thermal
protection gloves and a face shield are recommended when performing this
part of the procedure. The entire fusion process should be carried out in a
laboratory fume hood.
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6. Equipment and Supplies
NOTE: For samples with elevated activity concentrations of these radionuclides, labware should be used
only once due to potential for cross contamination unless the cleaning process is demonstrated to be
effective in removing residual contamination. The laboratory quality manual should provide guidance for
making these decisions.
6.1. Adjustable temperature laboratory hotplates.
6.2. Balance, top loading or analytical, readout display of at least ± 0.01 g.
6.3. Beakers, 250 mL capacity.
6.4. Crucibles, minimum capacity, 50 mL, platinum.
6.5. Dispensing pipette, 10 mL delivery volume. Alternately, a bottle-top dispenser, small
volume graduated cylinder, or any other device for delivering nominal 10 mL
volumes of reagent into a beaker or disposable cup.
6.6. Fisher blast burner or Meeker burner.
NOTE: Ordinary Bunsen burners will not achieve the high temperatures needed for fusion.
6.7. Ring stand with ceramic triangle (optional).
6.8. Drying oven.
6.9. Programmable muffle furnace capable of reaching at least 600 °C
6.10. Teflon spatula or glass rod.
6.11. Tongs for handling crucibles, platinum tipped.
6.12. Ten (10) mL transfer pipette.
6.13. Tweezers or forcep s.
NOTE: See Appendix A for a method for ball-milling and homogenization of soils.
6.14. Sample size reduction equipment (ball mill, paint shaker, etc) and screens. The
necessary equipment will be based on a laboratory's specific method for the process
of producing a dry uniformly ground sample from which to procure an aliquant
6.15. Filters, 0.45 micron, Environmental Express Flipmate filters or equivalent.
6.16. Plastic backed absorbent paper.
7. Reagents and Standards
NOTES: Unless otherwise indicated, all references to water should be understood to mean Type I
Reagent water (ASTM D1193; see Reference 16.9).
All reagents are American Chemical Society (ACS) grade or equivalent unless otherwise
specified.
7.1. Sodium carbonate, Na2CC>3, anhydrous. Note that anhydrous sodium carbonate is to
be stored in a desiccator.
7.2. Potassium carbonate, K2CO3, anhydrous. Note that anhydrous potassium carbonate is
to be stored in a desiccator.
7.3. Boric acid, H3BO3. Stored in a desiccator to eliminate any moisture uptake.
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7.4. Nitric acid (3 M), HNCb. Carefully add 190 mL of concentrated nitric acid to about
500 mL of water and dilute to 1 L with water.
7.5. Hydrofluoric acid (28M): Concentrated HF, available commercially.
7.6. Dry flux mix. Dry each reagent separately at 105 °C to remove moisture. Mix equal
weights of sodium carbonate, potassium carbonate, and boric acid and store in a
desiccator.
7.7. Radioactive tracers/carriers (used as yield monitors) and spiking solutions. Refer to
the chemical separation method(s) to be employed upon completion of this
dissolution technique. Tracers/carriers that are used to monitor radiochemical/
chemical yield should be added at the beginning of this procedure. This allows for
monitoring and correction for chemical losses in the combined digestion process, as
well as in the chemical separation method. Carriers used to prepare sample test
sources but not used for chemical yield determination (e.g., neodymium added for
microprecipitation of plutonium or uranium), should be added where indicated.
NOTE: In those samples where native constituents are present that could interfere with the
90C
determination of the chemical yield (e.g., strontium for Sr analysis) or with the creation of a
226T
sample test source (e.g., Ba for Ra analysis by alpha spectrometry), it may be necessary to
determine the concentration of these native constituents in advance of chemical separation (using
a separate aliquant of fused material) and make appropriate adjustments to the yield
calculations or amount of carrier added.
8. Sample Collection, Preservation, and Storage
Not Applicable.
9. Quality Control
9.1. Where the subsequent chemical separation technique requires the addition of carriers
and radioactive tracers for chemical yield determinations, these are to be added prior
to beginning the fusion procedure (or prior to charring of organic matter when
applicable), unless there is good technical justification for doing otherwise.
9.2. Batch quality control results shall be evaluated and meet applicable analytical project
specifications (APS) prior to release of unqualified data. In the absence of project-
defined APS or a project-specific quality assurance project plan (QAPP), the quality
control sample acceptance criteria defined in the laboratory's Quality Manual and
procedures shall be used to determine acceptable performance for this method.
9.2.1. An exception to this may need to be taken for samples of exceptionally high
activity where human safety may be involved.
9.3. Quality control samples are generally specified in the laboratory's Quality Manual or
in a project's analytical protocol specifications. At the very minimum the following
are suggested:
9.3.1. A laboratory control sample (LCS), which consists solely of the reagents used
in this procedure and a known quantity of radionuclide spiking solution, shall
be run with each batch of samples. The concentration of the LCS should be at
or near the action level or level of interest for the project
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9.3.2. One reagent blank shall be run with each batch of samples. The reagent blank
should consist solely of the reagents used in this procedure (including tracer or
carrier from the analytical method added prior to the fusion process).
9.3.3. A sample duplicate that is equal in size to the original aliquant should be
analyzed with each batch of samples. This provides assurance that the
laboratory's sample size reduction and sub-sampling processes are
reproducible.
9/11 9^Q 9^&
9.4. This method was validated separately for Am, Pu, and U.
9/11
9.4.1. An analytical action level of 1.5 pCi/g was used for Am, and a required
method uncertainty of 0.19 pCi/g was calculated for this action level. During
the validation process, a measurement uncertainty of 0.2 pCi/g or less was
achieved at and below 1.56 pCi/g. Above 1.5 pCi/g the calculated relative
required method uncertainty was 13%. During the validation process a relative
measurement uncertainty of 5.1% was achieved between 1.56 and 4.67 pCi/g.
9^Q
9.4.2. An analytical action level of 1.5 pCi/g was used for Pu, and a required
method uncertainty of 0.19 pCi/g was calculated for this action level. During
the validation process a measurement uncertainty of 0.15 pCi/g or less was
achieved at and below 1.89 pCi/g. Above 1.5 pCi/g the calculated relative
required method uncertainty was 13%. During the validation process a relative
measurement uncertainty of 5.1% was achieved for method validation
reference material spiked at 1.89 and 5.64 pCi/g.
9.4.3. An analytical action level of 12 pCi/g for 238U (natural uranium source), and a
required method uncertainty of 1.78 pCi/g was calculated for this action level.
During the validation process a measurement uncertainty of 0.59 pCi/g or less
was achieved at and below 13.7 pCi/g. Above 13.7 pCi/g the calculated
relative required method uncertainty was 13%. During the validation process a
relative measurement uncertainty of 3.8 % was achieved for method
validation reference material spiked 39.82 pCi/g. Similar results were
9^ A
obtained for U.
10. Calibration and Standardization.
10.1. Refer to the individual chemical separation and analysis methods for calibration and
standardization protocols.
11. Procedure
11.1. In accordance with the DQOs and sample processing requirements stated in the
project plan documents, remove extraneous materials from the soil using clean
forceps or tweezers.
11.2. Dry samples to constant weight in an oven at 105 °C.
11.3. Homogenize the sample so that a representative finely ground sample aliquant can be
removed.
11.4. Weigh 1-g aliquants into separate crucibles. Add an amount of tracer appropriate to
the method being used for each aliquant.
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11.5. For samples containing sufficient organic matter to cause concerns with the
subsequent fusion process, the samples should be further heated in a muffle furnace
with temperature programming (using temperature hold points to ensure sample
ignition does not occur) up to 600 °C to ensure combustion of all organic matter.
NOTE: Combustion of the organic matter in the sample can usually be accomplished over the
course of 1-2 hours for 1 gram samples of soil where the material is spread into a thin layer (up
to about 0.4 cm thick).
11.6. Add 15 mL of concentrated HF and evaporate to dryness on a hotplate at medium to
high heat (-300 °C). The evaporation should be complete in approximately 45
minutes.
11.7. Add about 3 g of dry flux mix (Step 7.6).
11.8. Warm the crucible slowly over the low flame of a Meeker or Fisher blast burner. The
initial heating may produce a vigorous reaction, which may last approximately 5
minutes. The crucible may be held over the flame with tongs or supported on a ring
stand with a ceramic triangle.
11.9. After the initial reaction has subsided, increase the heat gradually over 5 minutes until
the burner is at full flame.
11.10. Heat until the crucible glows bright red.
11.11. Continue heating over full flame for 5 minutes until no visible reaction is observed
and the melt is completely liquid and homogeneous.
11.12. Remove the crucible from the flame and swirl the contents so that the melt solidifies
on the sides of the crucible, approximately half-way up the sides. This will facilitate
the rapid dissolution of the cooled melt.
11.13. The crucible should be allowed to cool to the point so that addition of 3 M HNCb will
not create a violent reaction. Usually this is cool enough to touch.
11.14. When the crucible is moderately cool, carefully add approximately 10 mL of 3 M
FINOs by using a clean transfer pipette to wash the solid fusion cake down the inside
walls of the crucible. The reaction of the acid with the fused carbonate material may
be vigorous and care must be taken to avoid frothing the sample over the top of the
crucible. It may be necessary to place a lid on the crucible during the acid reaction to
avoid sample cross-contamination.
11.15. If necessary, heat the crucible gently on a hotplate and occasionally swirl the sample
to facilitate the dissolution of the fusion cake. Ensure that the entire fusion cake is
dissolved and that no solid material remains on the sides of the crucible.
11.16. If necessary, add additional 3 M HNOs in small (~ 1 mL) increments to facilitate the
complete dissolution of the fusion cake.
11.17. After the solution is cooled, boric acid may have precipitated. If visually present,
vacuum filter to remove excess undissolved boric acid.
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11.18. Transfer the dissolved sample to an appropriately sized beaker, rinsing the crucible
with 3 M HNOs to ensure a quantitative transfer of material. [See Step 12.2 for a
discussion of sample aliquanting.]
11.19. Proceed to the chemical separation methods. Omit the addition of tracers or carriers
added as yield monitors, as those reagents were added at the beginning of the fusion
process. However there may be carriers required in the subsequent separation
methods that will need to be added.
11.19.1. For actinide analyses, proceed directly to any of those methods listed in
Steps 1.1.1, 1.1.2, or 1.1.3, proceeding directly to Step 11.1.4, "Calcium
phosphate coprecipitation option" in the relevant separate method3 to
remove the excess sodium and potassium added during the fusion process.
12. Data Analysis and Calculations
12.1. Equations for determination of final result, combined standard uncertainty and
radiochemical yield (if required) are found in the corresponding chemical separation
and analysis methods, with the exception that the sample size is calculated as
described below, with the units being provided by the incident command, rather than
liters of water.
12.2. In cases where samples have elevated activity and multiple radionuclides are to be
analyzed, aliquants should be removed carefully, first measuring the mass or volume
of the entire final digestate. The mass or volume of the aliquants removed must also
be carefully measured to ensure that the sample aliquant size used for analysis is
accurately determined. The creation of multiple aliquants of a sample should be
thoroughly documented and reported in the case narrative.
For a single split the effective size of sample is calculated:
D
V=V,
a
r\ Equation 1
Where:
Vs = original sample size, in the units designated by the incident command
(e.g., 1 g, etc.)
Ds = mass or volume of the entire final digestate, created in Step 11.13 of this
procedure (e.g., 100 g, 50 mL, etc.).
Da = mass or volume of the aliquant of digestate used for the individual
analyses, as described in the various parts of Step 11.14-11.17 of this
procedure (e.g., 25 g, 5.0 mL, etc.). Note that the values for Da must be in
the same units used in Ds.
Va = sample aliquant size, used for analysis, in the units designated by the
incident command (e.g., kg, g, etc.).
3 Americium-241 in Water: Rapid Method for High-Activity Samples in Water, Plutonium-238 and Plutonium-
239/240 in Water: Rapid Method for High-Activity Samples', orlsotopic Uranium in Water: Rapid Method for High-
Activity Samples. See Reference 16.1.
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NOTE: For higher activity samples, additional dilution may be needed. In such cases, Equation 1
should be modified to reflect the number of splits and dilutions performed. It is also important to
measure the masses or volumes, used for aliquanting or dilution, to enough significant figures so
that their uncertainties have an insignificant impact on the final uncertainty budget.
12.2.1. In cases where the sample will not be split prior to analysis, the sample
aliquant size is simply equal to the original sample size, in the same units
requested by the incident command.
13. Method Performance
13.1. Method validation results should be archived by the laboratory.
13.2. Expected turnaround time per sample.
13.2.1. For representative, finely ground 1 -g aliquant of dried sample where
combustion to remove organic^ is required, combustion of the sample and
the subsequent fusion should add approximately 5 hours per batch to the
time specified in the individual chemical separation methods.
13.2.2. In some cases it may not be necessary to perform combustion to remove
organic matter. For representative, finely ground 1-g aliquant of dried
sample where combustion to remove organics is not required, the fusion
should add approximately 2 hours per batch to the time specified in the
individual chemical separation methods.
NOTE: Turnaround times for the subsequent chemical separation methods are given in those
methods for batch preparations.
14. Pollution Prevention
With the exception of minute quantities of combustion products, this method inherently
produces no significant pollutants. The sample and fusion reagents are retained in the final
product and are carried into the ensuing chemical separation techniques, which marginally
increases the salt content of the effluent waste. It is noted that if the sampled particulates
include radionuclides which may be volatile under the fusion conditions, these constituents
will be exhausted through fume hood system.
15. Waste Management
15.1. Refer to the appropriate chemical separation methods for waste disposal information.
16. References
16.1. U.S. Environmental Protection Agency (EPA). 2010. RapidRadiochemicalMethods
for Selected Radionuclides in Water for Environmental Restoration Following
Homeland Security Events, Office of Air and Radiation, National Air and Radiation
Environmental Laboratory. EPA 402-R-10-001, February. Revision 0.1 of rapid
methods issued October 2011. Available at: Environmental Research Laboratory.
Available at: www.epa.gov/erln/radiation.html.
16.2. U.S. Environmental Protection Agency (EPA). 2012. Rapid Method for Radium in
Soil Incorporating the Fusion of Soil and Soil-Related Matrices with the Radio-
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analytical Counting Method for Environmental Remediation Following Radiological
Incidents. Revision 0. Office of Air and Radiation, National Air and Radiation
Environmental Laboratory. Available at: www.epa.gov/narel/incident_guides.html.
16.3. U.S. Environmental Protection Agency (EPA). 2012. Rapid Method for Sodium
Carbonate Fusion of Soil and Soil-Related Matrices Prior to Strontium-90 Analyses
for Environmental Remediation Following Radiological Incidents. Revision 0. Office
of Air and Radiation, National Air and Radiation Environmental Laboratory.
Available at: www.epa.gov/narel/incident guides.html.
16.4. U.S. Environmental Protection Agency (EPA). 2009. Method Validation Guide for
Qualifying Methods Used by Radiological Laboratories Participating in Incident
Response Activities. Revision 0. Office of Air and Radiation, Washington, DC. EPA
402-R-09-006, June. Available at: www.epa.gov/narel/incident guides.html.
16.5. U.S. Environmental Protection Agency (EPA). 2012. Radiological Sample Analysis
Guide for Incident Response — Radionuclides in Soil. Revision 0. Office of Air and
Radiation, Washington, DC. EPA 402-R-12-006, September. Available at:
www.epa.gov/narel/incident guides.html.
16.6. MARLAP. 2004. Multi-Agency Radiological Laboratory Analytical Protocols
Manual. Volumes 1-3. Washington, DC: EPA 402-B-04-001A-C, NUREG 1576,
NTIS PB2004-105421. July. Available atwww.epa.gov/radiation/marlap/links.html.
16.7. U.S. Environmental Protection Agency (EPA). 2012. "Rapid Method for Sodium
Hydroxide Fusion of Concrete Matrices Prior to Am, Pu, Sr, Ra, and U Analyses."
Revision 0. Office of Air and Radiation, National Air and Radiation Environmental
Laboratory. Available at: www.epa.gov/narel/incident_guides.html.
16.8. U.S. Environmental Protection Agency (EPA). 2012. "RapidRadiochemicalMethod
for Total Radiostrontium (Sr-90) in Building Materials for Environmental
Remediation Following Radiological Incidents."Revision 0. Office of Air and
Radiation, National Air and Radiation Environmental Laboratory. Available at:
www.epa.gov/narel/incident guides.html.
16.9. ASTM Dl 193, "Standard Specification for Reagent Water" ASTM Book of
Standards 11.01, current version, ASTM International, West Conshohocken, PA.
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17. Flowcharts
17.1. Americium, Plutonium, Uranium
Steps 11.1-11.3
Remove detritus, add
tracer, dry,
homogenize and
aliquant
Step 11.4
Digest with HF and
evaporate to dryness
Yes
Combustion
at600°C
Step 11.5
Muffle combustion
needed?
Steps 11.6-11.13
Fusion using Na2CO3
Steps 11.14-11.18
Dissolve fused cake
using 3 M nitric acid
Proceed to the
Rapid Method for
• Americium
• Plutonium
• Uranium
in Water, Step
11.1.4, calcium
phosphate
precipitation
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Appendix A:
Rapid Technique for Milling and Homogenizing Soil Samples
Al. Scope and Application
ALL The method describes one approach for the rapid, gross preparation of soil samples
to yield dried, representative 1-2-g aliquant for radiochemical analysis of non-
volatile radionuclides. The method addresses steps for splitting, drying, and milling
of 50-2,000-g soil samples.
Al .2. This rapid milling method is designed to be used as a preparatory step for the
fusion of soils for Am, Pu, U, 90Sr, and 226Ra. It may also be applied to other
matrices whose physical form is amenable to pulverization in the ball mill. It is not
amenable to radionuclides that are volatile at 110 °C or below.
A1.3. The use of the term soil is not intended to be limiting or prescriptive. The method
described applies to soil-related materials such as sand, humic/fulvic soils, peat,
loam, sediment, etc.
Al .4. If the levels of activity in the sample are low enough to permit safe radiological
operations, up to 2 kg of soil can be processed.
A2. Summary of Method
A2.1. This method uses only disposable equipment to contact the sample minimizing the
risk of contamination and cross-contamination and eliminating concerns about
adequate cleaning of equipment.
A2.2. Extraneous material, such as vegetation, biota, or rocks or debris may be removed
prior to processing the sample unless the project requires that they be processed as
part of the sample.
NOTE: The sample mass is generally used for measuring the size of solid samples. The initial
process of acquiring a representative aliquant uses the volume of the sample, as the total
sample size is generally based on a certain volume of soil (e.g., 500 mL).
A2.3. The entire sample as received is split by coning and quartering until -75-150 mL of
soil are available for subsequent processing. If less than -450 mL of soil are
received, the entire sample is processed.
A2.4. The soil is transferred to a paint can and dried. Percent solids are determined, if
required.
A2.5. Grinding media (stainless-steel or ceramic balls or rods) are added, and the sample
is milled to produce a finely-ground, well-homogenized, powder with predominant
particle size less than 300 um.
A2.6. If the sample may contain discreet radioactive particles (DRPs), particles larger
than a nominal size of 150 um are screened for radioactivity, and further milled, or
processed with another appropriate method to ensure that they will be chemically
available for subsequent processing.
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A2.7. The resulting milled sample is stored in, and aliquanted directly from, the container
used for drying and pulverization.
A3. Definitions, Abbreviations, and Acronyms
A3.1. Discrete Radioactive Particles (DRPs or "hot particles"). Particulate matter in a
sample of any matrix where a high concentration of radioactive material is
contained in a tiny particle (um range).
A3.2. Multi-Agency Radiological Analytical Laboratory Protocol (MARLAP) Manual
(see Reference 16.6).
A4. Interferences
A4.1. Radi ol ogi cal Interference s
A4.1.1. Coning and quartering provides a mechanism for rapidly decreasing the
overall size of the sample that must be processed while optimizing the
representativeness of the subsampling process. By decreasing the time
and effort needed to prepare the sample for subsequent processing,
sample throughput can be significantly improved. Openly handling large
amounts of highly contaminated materials, however, even within the
containment provided by a fume hood, may pose an unacceptable risk of
inhalation of airborne contamination and exposure to laboratory
personnel from radioactive or other hazardous materials. Similarly, it
may unacceptably increase the risk of contamination of the laboratory.
A4.1.2. In such cases, coning and quartering process may be eliminated in lieu
of processing the entire sample. The time needed to dry the sample will
increase significantly, and the container size and the number and size of
grinding media used will need to be adjusted to optimize the milling
process. See ASTM C999 (see Reference A16.3) for an approach for
homogenization and milling of larger soil samples.
A4.2. The precise particle size of the milled sample is not critical to subsequent
processes. However, milling the sample to smaller particle sizes, and thorough
mixing, both facilitate representative sub-sampling by minimizing the amount of
sample that is not pulverized to fine mesh and must be discarded. Additionally,
subsequent fusion and digestion processes are more effective when performed on
more finely milled samples.
A4.3. This method assumes that radioactivity in the sample is primarily adsorbed onto the
surface of particles, as opposed to being present as a hot particle (see discussion of
DRPs below). Thus, nearly all of the activity in a sample will be associated with
sample fines. By visually comparing the sample to a qualitative standard of -50-
100 mesh size particles, it is possible to rapidly determine whether the sample is
fine enough to facilitate the subsequent fusion or digestion. This method assumes
that when greater than 95% of the sample is as fine or finer than the 50-100 mesh
sample, bias imparted from losses of larger particles will be minimal.
A4.4. If the sample was collected near the epicenter of an radiological dispersal device
(RDD) or improvised nuclear device (IND) explosion, it may contain millimeter- to
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micrometer-sized particles of contaminant referred to as "discrete radioactive
particles," or DRPs. DRPs may consist of small pieces of the original radioactive
source and thus may have very high specific activity. They may also consist of
chemically intractable material and present special challenges in the analytical
process. Even when size reduced to less than 50-100 mesh, these particles may
resist fusion or digestion of the solids into ionic form which can be subjected to
chemical separations.
A4.5. When DRPs may be present, this method isolates larger particles by passing the
sample through a disposable 50 mesh screen after which they can be reliably
checked for radioactivity. DRPs may reliably be identified by their very high
specific activity which is readily detectable since they show high count rates using
hand-held survey equipment such as a thin-window Geiger-Muller (G-M) probe.
A4.6. When present, DRPs may be further milled and then recombined with the original
sample. Alternatively, the particles, or the entire sample may need to be processed
using a different method capable of completely solubilizing the contaminants such
that the radionuclides they contain are available for subsequent chemical
separation.
A5. Safety
A5.1. General
A5.1.1. Refer to your safety manual for concerns of contamination control,
personal exposure monitoring and radiation dose monitoring.
A5.1.2. Refer to the laboratory chemical hygiene plan for general chemical
safety rules
A5.2. Radiological
A5.2.1. Refer to your radiation safety manual for direct on working with known
or suspected radioactive materials.
A5.2.2. This method has the potential to generate airborne radioactive
contamination. The process should be carefully evaluated to ensure that
airborne contamination is maintained at acceptable levels. This should
take into account the activity level, and physical and chemical form of
contaminants possibly present, as well as other engineering and
administrative controls available.
A5.2.3. Hot Particles (DRPs)
A5.2.3.1. Hot particles will usually be small, on the order of 1 mm or
less. Typically, DRPs are not evenly distributed in the media,
and their radiation emissions are not uniform in all directions
(anisotropic). Filtration using a 0.45-um filter or smaller may
be needed following subsequent fusion to identify the
presence of smaller DRPs.
A5.2.3.2. Care should be taken to provide suitable containment for
filter media used in the pretreatment of samples that may
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have DRPs, because the particles become highly statically
charged as they dry out and will "jump" to other surfaces
potentially creating contamination-control issues.
A5.3. Method-Specific Non-Radiological Hazards
A5.3.1. This method employs a mechanical shaker and should be evaluated for
personnel hazards associated with the high kinetic energy associated
with the milling process.
A5.3.2. This method employs a mechanical shaker and involves vigorous
agitation of steel or ceramic balls inside steel cans. The process should
be evaluated to determine whether hearing protection is needed to
protect the hearing of personnel present in the area in which the
apparatus is operated.
A6. Equipment and supplies
A6.1. Balance, top-loading, range to accommodate sample size encountered, readability
to ±1%.
A6.2. Drying oven, at 110±10 °C.
A6.3. Steel paint cans and lids (pint, quart, 2-quart, 1-gallon, as needed).
A6.4. Steel or ceramic grinding balls or rods for ball milling, ~15-mm diameter. The size
and number of grinding media used should be optimized to suit the types of sand or
soil, the size of the can, and the volume of soil processed.
A6.5. Wire cloth - nominal 48 mesh size (-300 um).
A6.6. Sieves, U.S. Series No. 50 (300-um or 48 mesh) and U.S. Series No. 100 (150-um
or 100 mesh).
A6.7. Red Devil 5400 mechanical paint shaker, or equivalent mechanical.
A6.8. Disposable scoop, scraper, tongue depressor or equivalent.
A7. Reagents and Standards
No reagents needed.
A8. Sample Collection, Preservation and Storage
A8.1. Samples should be collected in appropriately sized plastic, metal or glass
containers.
A8.2. No sample preservation is required. If samples are to be held for an extended period
of time, refrigeration may help minimize bacterial growth in the sample.
A8.3. Default sample collection protocols generally provide solid sample volumes
equivalent to approximately 500 mL of sample. Such samples will require two
splits to obtain a -100 mL sample.
A9. Quality Control
A9.1. Batch quality control results shall be evaluated and meet applicable Analytical
Project Specifications (APS) prior to release of unqualified data. In the absence of
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project-defined APS or a project-specific quality assurance project plan (QAPP),
the quality control sample acceptance criteria defined in the laboratory quality
manual and procedures shall be used to determine acceptable performance for this
method.
A9.2. Quality control samples should be initiated as early in the process as possible.
Since the risk of cross-contamination using this process is relatively low, initiating
blanks and laboratory control samples at the start of the chemical separation
process is acceptable. If sufficient sample is available, a duplicate sample should be
prepared from the two discarded quarters of the final split of the coning and
quartering procedure.
A10. Procedure
NOTE: This method ensures that only disposable equipment comes in contact with sample materials to
greatly minimize the risk sample cross-contamination and concerns about adequate cleaning of
equipment.
A10.1. Estimate the total volume of sample, as received.
NOTES: If the sample is dry, the risk of resuspension and inhalation of the solids may be determined
to be unacceptable. In such cases, the entire sample may be processed in a larger can. The
drying and milling time will be increased, and more grinding media will be required to obtain
a satisfactory result
The next step uses absorbent paper in the reverse fashion for the normal use of this type of
paper; it allows for a smooth division of the sample and control of contamination.
Al 0.1.1. Spread a large piece of plastic backed absorbent paper, plastic side up in
a hood.
A10.1.2. If the sample volume is less than -450 mL, there is no benefit to coning
and quartering.4
A10.1.2.1. Carefully pour the sample onto the paper.
A10.1.2.2. Remove extraneous material, such as vegetation, biota, or
rocks or debris unless the project requires that such material
be processed as part of the sample. Continue with Step
A10.1.6.
A10.1.2.3. If the sample volume is greater than -450 mL, carefully pour
the entire sample into a cone onto the paper.
Remove extraneous material, such as vegetation, biota, or
rocks or debris unless the project requires that such material
be processed as part of the sample.
A10.1.3. If levels of gross activity in the sample permit, the sample is split at
least twice using the coning and quartering steps that follow.
NOTE: Unused quarters are considered representative of the original sample and
may be reserved for additional testing. The process should be carried out
4 See IUPAC Gold Book, Coning and Quartering in Analytical Chemistry, available at:
goldbook.iupac.org/C01265.html
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expediently to minimize loss of volatile components in the sample, especially
volatile components or percent solids are to be determined.
A10.1.4. Spread the material into a flat circular cake of soil using a tongue
depressor or other suitable disposable implement. Divide the cake
radially and return two opposing quarters to the original sample
container.
A10.1.5. Reshape the remaining two quarters into a smaller cone, and repeat Step
A10.1.3 until the total volume of the remaining material is
approximately 100-150 mL.
NOTE: Tare the can and lid together. Do not apply an adhesive label rather label
the can with permanent marker since the can will be placed in a drying oven. The
lid should be labeled separately since it will be removed from the can during
drying
A10.1.6. Transfer the coned and quartered sample to a tared and labeled 1-pint
paint can. If the total volume was less than -450 mL, transfer the entire
sample to a tared and labeled 1-quart paint can.
NOTE: Constant mass may be determined by removing the container from the
oven and weighing repeatedly until the mass remains constant with within 1% of
the starting mass of the sample. This may also be achieved operationally by
observing the time needed to ensure that 99% of all samples will obtain constant
mass.
A10.2. Place the can (without lid) in an oven at 110 ± 10 °C and dry the soil to constant
mass.
A10.3. Weigh the combined mass of the can, sample, and lid. If the percent solids are
required see Step A12.1 calculations.
A10.4. Add five 1.5-cm stainless-steel or ceramic balls or rods to the can. Replace the lid
and seal well.
A10.5. Shake the can and contents for 5-15 minutes, or longer, as needed to produce a
finely-milled, well-homogenized, sample.
NOTE: Although the precise particle size of the milled sample is not critical, complete
pulverization and fine particle size facilitates representative sub-sampling and subsequent
fusion or digestion processes. A qualitative standard can be prepared by passing quartz sand
or other milled material through a 50-mesh and then a 100-mesh screen. The portion of the
sample retained in the 100 mesh screen can be used as a qualitative visual standard to
determine if samples have been adequately pulverized.
A10.6. Visually compare the resulting milled sample to a qualitative 50-100 mesh
pulverized sample (~150-300-um or 50-100 mesh using the Tyler screen scale).
The process is complete once 95% of the sample (or greater) is as fine, or finer,
than the qualitative standard. If, by visual estimation, more than -5% of total
volume of the particles in the sample appear to be larger than the particle size in the
standard, return the sample to the shaker and continue milling until the process is
complete.
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A10.7. Following milling, a small fraction of residual larger particles may remain in the
sample.
A10.7.1. If the sample was collected close to the epicenter of an RDD or IND
explosion, it may also contain particles of contaminant referred to as
"discrete radioactive particles" or DRPs. In such a case, the larger
particles should be isolated by passing through a disposable 48 mesh
screen and checked for radioactivity. DRPs are readily identified by
their very high specific activity which is detectable using hand-held
survey equipment such as a thin-window G-M probe held within an inch
of the particles.
A10.7.1.1. If radioactivity is clearly detected, the sieved material is
returned to the can and ball milled until the desired mesh is
obtained. In some cases, these materials may be resistant to
further pulverization and may need to be processed
according to a method specially designed to address highly
intractable solids.
A10.7.1.2. If the presence of DRPs is of no concern, the larger particles
need not be included in subsequent subsamples taken for
analysis. It may be possible to easily avoid including them
during aliquanting with a disposable scoop. If not, however,
they should be removed by sieving through a nominal 50
mesh screen (disposable) prior to further subsampling for
subsequent analyses.
A10.8. Sample fines may be stored in, and aliquanted directly from, the container used for
drying and pulverization.
All. Calibration and Standardization
Balances used shall be calibrated using National Institute of Standards and Technology
(NIST)-traceable weight according to the process defined by the laboratory's quality
manual.
A12. Data Analysis and Calculations
A12.1. The percent solids (dry-to-as-received mass ratio) for each sample is calculated
from data obtained during the preparation of the sample as follows:
% Solids = Mdly'Mtare x 1 00
M ' M
tare
Where:
Mdry = mass of dry sample + labeled can + lid (g)
Mtare = tare mass of labeled can + lid (g)
Mas rec, = mass of sample as received + labeled can + lid (g)
A12.2. If requested, convert the equivalent mass of sample, as received, to dry mass as
follows:
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% Solids
DrySampleEquivalent = Mtotal.asra
x -
100
Where:
Mtotai-as rec. = total mass of sample, as received (g)
A12.3. Results Reporting
The result for percent solids and the approximate total mass of sample as received
should generally be reported for each result.
A13. Method Performance
A13.1. Results of method validation performance are to be archived and available for
reporting purposes.
A13.2. Expected turnaround time is about 3 hours for an individual sample and about 4
hours per batch.
A14. Pollution Prevention.
Not applicable.
A15. Waste Management.
All radioactive and other regulated wastes shall be handled according to prevailing
regulations.
A16. References
A16.1. A. D. McNaught and A. Wilkinson, Coning and Quartering in Analytical
Chemistry, IUPAC Compendium of Chemical Terminology, The Gold Book.,
Second Edition, Blackwell Science, 1997 (online edition).
A16.2. ALS Environmental, Fort Collins, SOP 736.
A16.3. ASTM C 999-05, Standard Practice for Soil Sample Preparation for the
Determination of Radionuclides, Volume 12.01, ASTM, 2005.
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A17. Tables, Diagrams, and Flow Charts
A17.1. Homogenization
Steps A10.1.1-A10.1.2
Estimate sample volume,
remove detritus
Step A10.1.3
Cone and quarter, transfer
aliquant to tared container
Step s A10.2-A10.3
Dry at 110 °C to constant
mass
Step s A10.4-A10.5
Add ceramic or steel balls
and mix
Steps A10.6-A10.7
Visual inspection for
homogeneity and particle
size
StepAlO.8
Aliquant sample and store
residual
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